Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/90—Regeneration or reactivation
  • B01J23/96—Regeneration or reactivation of catalysts comprising metals, oxides or hydroxides of the noble metals
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G59/00—Treatment of naphtha by two or more reforming processes only or by at least one reforming process and at least one process which does not substantially change the boiling range of the naphtha
  • C10G59/06—Treatment of naphtha by two or more reforming processes only or by at least one reforming process and at least one process which does not substantially change the boiling range of the naphtha plural parallel stages only

Definitions

• a superior reforming catalyst which contains platinum and alumina as the principal constituents and frequently contains minor amounts of a halogen, particularly fluorine or chlorine.
• This catalyst is capable of increasing the octane number 'of hydrocarbon stocks such as straight-run gasolines and naphthas to values that are substantially higher than those that ordinarily can be reached by thermal reforming.
• the yield-octane number relationship is much better than are the corresponding relationships obtained in either thermal reforming or in most of the prior catalytic reforming processes. It has been found that by an appropriate selection of operating conditions and by charging a feed stock of low end point, this catalyst can be used for a number of weeks without regeneration.
• the rate of carbon formation can be greatly reduced if the charging stock is divided into two or more fractions of diiferent boiling ranges and each of said fractions is processed under particular conditions of intensity approaching the optimum for each fraction.
• the present invention provides a process by means of which greatly increased catalyst life is obtained with poor stocks as well as with good stocks. In addition, a superior yield-octane number relationship often is obtained.
• the process according to the present invention comprises fractionating a hydrocarbon fraction containing 'naphthenes into a high boiling fraction and a lower boiling fraction, reforming the lower boiling fraction in the presence of added hydrogen and a catalyst comprising platinum and alumina, reforming the high boiling fraction 2,773,809 V PatentedDec. 1 1,
• This intensity factor of the process may be calculated by the following equation:
• Tr- Tn R I PGL)2 2 22 an PH2L where:
• PGL partial pressure of lower boiling fraction in zone in which said fraction is reformed p. s. i. a.
• Pen partia1 pressure of high boiling fraction in zone in which said fraction is reformed
• Pnzn hydrogen partial pressure in zone in which the high boiling fraction is reformed
• Pnzn hydrogen partial pressure in zone in which the lower boiling fraction is reformed
• p. s. i. a. TL elfective average temperature in zone in which the lower boiling fraction is reformed
• Tn effective average temperature in zone in which the high boiling fraction is reformed
• the hydrocarbon stocks that may be converted in accordance with our process comprise hydrocarbon fractions containing naphthenes.
• the preferred stocks are those containing naphthenes and paraflins, although minor amounts of aromatics also may be present.
• This preferred class includes straight-run gasolines, natural gasolines, and the like.
• the charge may comprise olefinic gasolines including, for example, thermally cracked gasoline, coker distillate, catalytically cracked gasoline, etc., or mixtures thereof, and more particularly mixtures of one or more of these stocks with saturated stocks including, for example, straight-run and/ or natural gasolines.
• the gasoline may be a full boiling range gasoline having an initial boiling point within the range of from about 50 to about 100 F.
• the catalysts comprising platinum and alumina that are preferred for use in the present process may contain substantial amounts of platinum but, for economic as well as for product yield and quality reasons, the platinum content usually will be within the range of from about 0.05 to about 5.0 weight percent.
• a particularly eflfective catalyst of this type contains a halogen, especially chlorine or fluorine, in relatively minor amounts, generally within the range of from about 0.1% to about 8% and in most cases not more than about 3% by weight of the alumina (which corresponds, for example, to 158 gram equivalents of fluorine/ 100,000 grams of alumina) on a dry alumina basis.
• One method of preparing the catalyst comprises adding a suitable alkaline reagent such as ammonium hydroxide or carbonate to a salt of aluminum, such as aluminum chloride, aluminum sulfate, aluminum nitrate, and the like, in an amount suflicient to form aluminum hydroxides, which upon drying, can be converted to alumina.
• a suitable alkaline reagent such as ammonium hydroxide or carbonate
• a salt of aluminum such as aluminum chloride, aluminum sulfate, aluminum nitrate, and the like
• the halogen may be added to the resultant slurry in the form of an acid such as hydrogen fluoride or hydrogen chloride, or as a volatile salt such as ammonium fluoride or ammonium chloride.
• a colloidal suspension of platinic sulfide is then prepared by introducing hydrogen sulfide into an aqueous solution of chloroplatinic acid until said solution reaches a constant color, which usually is a dark brown.
• the resultant colloidal suspension of platinic sulfide is commingled with the aluminum hydroxide slurry at room temperature followed by stirring toobtain intimate mixing.
• the resulting materials are then dried at a temperature of from about 200 to about 400 F. for a period of from about 4 to about 24 hours or more to form a cake.
• the dried material will then be converted into pills or other shaped particles.
• the catalyst may be subjected to a calcination or reduction treatment at a high temperature, of the order of 8001200 F., prior to use.
• catalyst comprising platinum and alumina in the specification and appended claims is intended to include composites which contain platinum and alumina in any event and which, moreover, may contain other components such as, for example, silica and/or minor amounts of halogen.
• the exact manner inwhich the halogen or halide ion is present in the catalyst is not known although it is believed to be present in the form of a chemical combination or loose complex with the alumina and/or platinum components. Because the exact chemical constitution of such halogen-containing catalysts is not known, we sometimes refer to them as catalysts comprising platinum, alumina, and a halogen.
• the other catalysts may comprise alumina-platinum, silica-alumina-platinum, silicazirconia-platinum, silica-alumina-zirconia-platinum, silicamagnesia platinum, silica-alumina magnesia platinum, silica-thoria-platinum, silica-alumina-thoria-platinum, alumina-boria-platinum, silica-platinum, etc., which catalysts also may contain halogen.
• the temperature at which the light fraction is reformed may be 880 F. and the temperature at which the heavy fraction is reformed may be 900 F.
• the other variables are sufliciently more intense in the operation with the light fraction so that the resultant overall intensity of reforming is greater with the light fraction than it is with the heavy fraction, the requirements of our process have been met.
• the hydrocarbon reactant partial pressure ordinarily should lie within the range of from about 20 to about 400 p. s. i. a.
• the reason for the lower limit is found in the fact that in the presence of hydrogen the catalyst employed in our process promotes 'hydrocracking and isomerization of said stocks as well as aromatization.
• the hydrocarbon partial pressure is much below about 20 pounds, the hydrogen/hydrocarbon ratio must be excessive in order that the hydrogen partial pressure will be sufiiciently high to effectively bring about hydrocracking.
• hydrocarbon partial pressure is greater than about 400 pounds, the total pressure becomes excessive even at fairly low hydrogen/hydrocarbonratios of the order of 4:1.
• the hydrogen partial pressure ordinarily should be within the range of from about 200 to about p. s. i. a. and preferably from about 300 to about 1000 p. 's. i. a. for the high boiling fractions. It sould ordinarily be within the range of from about to about 1000 and preferably from about tolabout 650 s. i. a. for the lower boiling fractions.
• At hydrogen partial pressures below the indicated lower limits there is little or no hydrocracking and there is excessive production of catalyst carbon.
• the proportion of hydrocracking increases, aromatization decreases, and hydrogen consumption is encountered.
• the intensity of the reforming operation decreases as the hydrogen partial pressure is increased.
• the reforming temperatures employed in our process generally lie within the range of about 750 to about 1000 F. At temperatures much below about 750 F. the hydrocarbon conversion reactions are quite slow and very low space velocities must be employed to obtain appreciable conversions. In addition, an unfavorable naphthene-aromatic equilibrium is encountered. At reaction temperatures above about 1000 R, an appreciable amount of thermal reaction takes place accompanied by poorer liquid recovery and more rapid catalyst deactivation. In the correlation according to the formula of relative intensity that is more fully explained hereinafter, effective average catalyst temperatures are used, said temperatures being obtained by dividing the reactor into convenient segments, each of which may be considered as being approximately at a constant temperature.
• the relative reaction rate coefiicient for each segment at its average temperature is obtained and this coefficient is multiplied by the fractional part of the bed corresponding to the segment.
• the resultant products are added up for the entire-bed, and the sum is the effective average rate coeflicient for the bed.
• the temperature corresponding to this reaction rate coefficient is then the effective average temperature.
• the correlation is designed to give only the intensity of the operating conditions with the light fraction relative to the intensity of the operating conditions with the heavy fraction, i. e., a relative intensity, we have found that the arithmetic average temperature may be employed with satisfactory results.
• the arithmetic average temperature is obtained by taking a fairly large number of temperature points through the bed and simply averaging them. This method avoids the rather involved method of obtaining the efiective average temperature.
• the intensity of reforming increases with increasing temperature.
• weight hourly spaced velocities used in our process usually will lie within the range of from about 0.2 to about 40.
• space velocity is an extensive factor in our process. In a given operation, the intensive variables ordinarily will be selected in accordance with the teachings herein set forth.
• the space velocity may then be adjusted to obtain vthe desired reforming severity. The severity of reforming increases as the space velocity is decreased.
• the lower boiling fraction may be reformed in one reaction zone at the same time that the high boiling fraction is being reformed in another reaction zone.
• This mode of processing has the advantage of permitting continuous reforming treatment of both fractions.
• the reforming of the two fractions may be effected during alternating periods of operation in asingle reaction zone.
• the gasoline charge may be fractionated in any suitable manner and with the aid of conventional fractionating devices.
• each fraction is preferably carried out by commingling the hydrocarbon fraction with the appropriate amount of hydrogen or gas of high hydrogen content, such as recycle hydrogen gas separated from the products of the process, passing the mixture of hydrogen and hydrocarbon fraction through a tubular heater wherein the mixture is heated to reaction temperature, passing the heated effluent from the heater into and through a heat-insulated reaction chamber and the catalyst contained therein, preferably in a generally downward direction through a stationary bed of catalyst particles in such chamber, withdrawing the eflluent from the reaction chamber through a line containing a pressure control valve and through a condenser into a receiver wherein recycle hydrogen gas is separated from the cooled and liquefied reaction products under an appropriate pressure, and thereafter recovering the reformed gasoline in a conventional manner.
• hydrogen or gas of high hydrogen content such as recycle hydrogen gas separated from the products of the process
• a stream of the hydrogen gas separated in the receiver is recirculated to the inlet side of the tubular heater to commingle with the stream of gasoline fraction entering the same.
• both the high boiling fraction and the low boiling fraction are subjected simultaneously to reforming treatment in separate reaction zones it is preferred to commingle the efiiuents of the two separate catalytic treatments and then subject the commingled streams to condensation, cooling, hydrogen gas separation and product recovery- Excess hydrogen gas produced in the process is usually removed from the system in the stage thereof wherein the reformed gasoline is recovered.
• a series of two or more reaction chambers preferably with intervening heating between chambers, may be employed for the separate processing of the light and/ or heavy fractions.
• Example I ing conditions of reaction, the hydrogen being continuous-z 1y separated from the reforming products and recycled to the reaction zone:
• Fraction Light Heavy Hydrocarbon boiling range F -200 200-400 Temperature of reaction zone, "F 930 920 Total pressure in reaction zone, p. s. i. a 300 500 M01 ratio, hydrogen to hydrocarbon 4:1 4. 5:1 Volume percent hydrocarbon gas in hydrogen stream 12 13. 5 Space velocity, weight of hydrocarbon charged per hour per weight of catalyst 2 2,
• Low-boiling fraction Mols total recycle gas per mol low boiling fraction Partial pressure of H2 in reaction zone (Pn n) 4 300( )-21e p. s. 1. a.
• Partial pressure of low boiling fraction in reaction zone (PGL) 300( ) 54 p. s. i. a.
• High-boiling fraction Mols total recycle gas per mol high boiling fraction Partial pressure H2 in reaction zone (Pn n);
• a similarly improved operation results if, instead of increasing the hydrogen partial pressure in the reforming zone for the high boiling'frac'tion by increasing the mol ratio of hydrogen to high boiling hydrocarbon, as indicated, the effective average temperature of the reaction of the high boiling fraction is decreased. For example, by decreasing Tn from 920 to 910 F., the relative intensity is increased to about 12.
• the invention permits to achieve longer catalyst life. Also a better yieldoctane number relationship is obtained by the reforming of gasoline hydrocarbon stocks in accordance with the invention as described above, the reason for this better relationship being two-fold, namely the diminution of carbonization reactions and the favorable effect of the relative intensity in the reforming on the octane numbers of the resultant reformed gasoline fractions.
• a process which comprises separating a hydrocarbon reforming charge stock into a higher boiling fraction and a lower boiling fraction, reforming the lower boiling fraction in the presence of added hydrogen and as said first mentioned catalyst, butat a higher hydrogen partial pressure than utilized in the reforming of the lower boiling fraction, and subjecting the lower boiling fraction to an intensity of reforming conditions which is at least 10 times as great as the intensity of the reforming :conditions to which the higher boiling fraction is subjected.
• a reforming process which comprises fractionating a hydrocarbon reforming charge stock containing naph: themes and boiling below about 425 F. into a higher and a lower boiling fraction, reforming the lower boiling fraction in the presence of added hydrogen and a catalystcomprising platinum and alumina, separately reforming the higher boiling fraction in the'presence of added hydrogen and a catalyst comprising platinum and alumina of substantially the same composition as said first mentioned catalyst, but at a higher hydrogen par-tialpressure than utilized in the reforming of the lower boiling fraction, and subjecting the lower boiling fraction to an intensity of reforming conditions which is at least 10 times as great as the intensity of the reforming conditions to which the higher boiling fraction is subjected.
• charge stock containing naphthenes boiling in the gasoline range which comprises separating said stock into a light fraction and a heavier fraction, and separately reforming said fractions in the presence of hydrogen and platinum-containing catalyst, the light fraction being subjected to an intensity of reforming conditions at least 10 times greater than the heavier fraction and the latter being reformed at a hydrogen partial pressure at least 100 pounds per square inch higher than that at which said light fraction is reformed.
• a process for the conversion of a hydrocarbon reforming charge stock containing naphthenes boiling inthe gasoline range which comprises separating said stock into a light fraction and a heavier fraction, reforming said light fraction in a first zone in the presence of hydrogen and a body of catalyst comprising platinum and alumina, and separately reforming said heavier fraction in a second zone at less intense conditions in the presence of another body of'catalyst comprising platinum and alumina and at a hydrogen partial pressure at least'100 pounds per square inch higher than that at which said light fraction is reformed, the intensity of the reforming condi-. tions in said first zone being at 1east'10 times as great as that in said second zone.

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• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

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• 1953
  • 1953-11-16 FR FR1090846D patent/FR1090846A/fr not_active Expired
  • 1953-11-16 GB GB31672/53A patent/GB742563A/en not_active Expired
  • 1953-11-16 US US392489A patent/US2773809A/en not_active Expired - Lifetime
  • 1953-11-16 DE DEU2491A patent/DE1001790B/de active Pending
  • 1953-11-16 NL NL182850A patent/NL92595C/xx active

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